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沙丁胺醇乙基化β环糊精包合物的研制 被引量:6
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作者 冯波 何仲贵 +1 位作者 赵临襄 赵春顺 《中国药学杂志》 EI CAS CSCD 北大核心 2002年第3期195-198,共4页
目的 制备沙丁胺醇 乙基化 β环糊精包合物 ,考察其有关性质。方法 采用冷冻干燥法和研磨法制备其包合物。结果 经ESI MS和X射线衍射法鉴定 ,表明沙丁胺醇与乙基化 β环糊精 (ECD)确已形成包合物 ,ESI MS和含量测定证明包合物主、... 目的 制备沙丁胺醇 乙基化 β环糊精包合物 ,考察其有关性质。方法 采用冷冻干燥法和研磨法制备其包合物。结果 经ESI MS和X射线衍射法鉴定 ,表明沙丁胺醇与乙基化 β环糊精 (ECD)确已形成包合物 ,ESI MS和含量测定证明包合物主、客分子比为 1∶1;包合物的相溶解度图为BI 型 ,表明难溶性包合物形成。结论 沙丁胺醇 乙基化 β环糊精包合物可明显降低沙丁胺醇的溶解度和释放度 ,说明ECD可作为一种缓释载体。 展开更多
关键词 沙丁胺醇 乙基化β环糊清 包合物 研制
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基于线图的无β环混合依赖分解条件及算法
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作者 刘文远 郝忠孝 《软件学报》 EI CSCD 北大核心 2000年第12期1656-1659,共4页
无β环数据库模式具有很多优良的特性 ,以往的研究都局限在图论的范畴内 ,而没有考虑数据库的其他规范化特性 .在混合依赖基概念的基础上 ,定义了严格无冲突、扩展严格无冲突等概念 ,并证明了在混合环境下得出的无损联接、保持依赖、无... 无β环数据库模式具有很多优良的特性 ,以往的研究都局限在图论的范畴内 ,而没有考虑数据库的其他规范化特性 .在混合依赖基概念的基础上 ,定义了严格无冲突、扩展严格无冲突等概念 ,并证明了在混合环境下得出的无损联接、保持依赖、无 β环且满足 4 N F的分解的充要条件是 ,混合依赖集是扩展严格无冲突的 .据此 ,给出了判断严格无冲突及混合环境下无β环分解算法 ,并分析了算法时间的复杂度是线性的 .最后 ,给出基于线图的实例验证 . 展开更多
关键词 数据库模式 混合依赖 线图 β环 无损联接 保持依赖
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无内部冲突数据库模式满足P3及无β环判定问题研究
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作者 郝忠孝 顾照鹏 《计算机研究与发展》 EI CSCD 北大核心 2008年第6期1056-1063,共8页
通过分析在FD集F的最小归并依赖集D无弱左部冲突、弱右部冲突时相邻归并依赖所具有的性质和特征,提出了左部集冲突、蕴含集间冲突和主归并依赖冲突等概念,在此基础上证明了在FD集F无内部冲突且最小归并依赖集D中存在弱左、右部冲突、左... 通过分析在FD集F的最小归并依赖集D无弱左部冲突、弱右部冲突时相邻归并依赖所具有的性质和特征,提出了左部集冲突、蕴含集间冲突和主归并依赖冲突等概念,在此基础上证明了在FD集F无内部冲突且最小归并依赖集D中存在弱左、右部冲突、左部集冲突、蕴含集间冲突和主归并依赖冲突时模式分解为满足P3为有β环的结论,并给出了左部集冲突、蕴含集间冲突和主归并依赖冲突的判定算法及分析,为进一步研究无β环的分解奠定了基础. 展开更多
关键词 无内部冲突 β环 模式分解 超图 线图
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吸积盘的最小β环和光度爆发区
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作者 吴德金 童彝 《天文学报》 CSCD 北大核心 1992年第4期403-407,共5页
对标准吸积盘模型上压力参数β的径向分布的分析表明,它最重要的特征是在吸积盘的内部区域(R_0~1.9R_(in))有一最小β环存在.对具有极限环演化行为的吸积盘模型,这一最小β环的存在有着重要意义,它不仅决定了光度爆发的幅度,也使产生... 对标准吸积盘模型上压力参数β的径向分布的分析表明,它最重要的特征是在吸积盘的内部区域(R_0~1.9R_(in))有一最小β环存在.对具有极限环演化行为的吸积盘模型,这一最小β环的存在有着重要意义,它不仅决定了光度爆发的幅度,也使产生爆发的区域被限制在一个适当的范围内. 展开更多
关键词 吸积盘 β环 稳定性 光度 爆发区
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基于超图和线图的β环与其它环的关系
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作者 刘文远 刘永炎 于洋 《燕山大学学报》 CAS 2001年第1期69-72,共4页
通过大量图例,以β环为中心,系统地讨论了基于超图的β环与纯环、β环与弱环、弱β环与γ环、β环与γ环的关系,以及基于线图的无β环与无α环、无β环与无α环之间的关系。
关键词 数据库模式 超图 线图 β环
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无β环数据库模式研究
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作者 刘文远 郝忠孝 《燕山大学学报》 CAS 2000年第1期80-83,共4页
无β环数据库模式是无环模式分类中的一种,无β环是相对容易满足的,且具有子图的无环性,因此具有很好的实用价值。本文给出了无β环的各种定义和定理,最后讨论了无β环的基于超图和线图的几种多项式时间算法。
关键词 β环 数据库模式 超图 数据库
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酸催化制备β环香叶基苯基砜
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作者 莫谷妹 《广州化工》 CAS 2021年第13期47-49,共3页
β环香叶基苯基砜是制备维生素A、β胡萝卜素的重要中间体,在化工、制药、化妆品等领域有着广泛的应用,其合成途径主要是由香叶基苯基砜经环合反应得到。本文深入研究了在硫酸或对甲苯磺酸催化条件下,不同的酸浓度、用量、温度等因素对... β环香叶基苯基砜是制备维生素A、β胡萝卜素的重要中间体,在化工、制药、化妆品等领域有着广泛的应用,其合成途径主要是由香叶基苯基砜经环合反应得到。本文深入研究了在硫酸或对甲苯磺酸催化条件下,不同的酸浓度、用量、温度等因素对反应的影响,发现硫酸比对甲苯磺酸效果好,得到其最佳实验条件,最终成功制备得到纯度为96%以上的β环香叶基苯基砜纯品。 展开更多
关键词 香叶基苯基砜 β环香叶基苯基砜
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信号通路在子宫内膜异位症发病中的作用研究进展 被引量:6
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作者 冯婉琴 刘敏娟 马颖 《山东医药》 CAS 2018年第42期96-99,共4页
子宫内膜异位症(EMs)具有种植生长、侵袭、远处转移等类似恶性肿瘤的特点,是造成痛经、不孕以及盆腔疼痛的首要原因,其发病率及复发率均很高。目前,EMs的发病机制仍不明确。近年研究表明,EMs中存在多种细胞凋亡/存活信号通路的异常,如... 子宫内膜异位症(EMs)具有种植生长、侵袭、远处转移等类似恶性肿瘤的特点,是造成痛经、不孕以及盆腔疼痛的首要原因,其发病率及复发率均很高。目前,EMs的发病机制仍不明确。近年研究表明,EMs中存在多种细胞凋亡/存活信号通路的异常,如核因子κB信号通路、Shh信号通路、Wnt/β-catenin信号通路、TGF-β/Smad信号通路、Notch信号通路、磷脂酰肌醇3激酶/蛋白激酶B/哺乳动物雷帕霉素靶蛋白信号通路。这些通路的异常启动及其复杂的相互作用会导致异位内膜组织的异常增殖、分化、侵袭及炎症反应,进而促进异位病灶形成。 展开更多
关键词 子宫内膜异位症 信号通路 核因子ΚB信号通路 SHH信号通路 Wnt/β环连蛋白信号通路 TGF-Β/SMAD信号通路
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Biomimetic asymmetric Michael addition reactions in water catalyzed by amino-containing β-cyclodextrin derivatives 被引量:4
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作者 朱庆英 沈海民 +1 位作者 杨祖金 纪红兵 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2016年第8期1227-1234,共8页
Nineβ‐cyclodextrin derivatives containing an amino group were synthesized via nucleophilic sub‐stitution from mono(6‐O‐p‐tolylsulfonyl)‐β‐cyclodextrin and used in asymmetric biomimetic Mi‐chael addition re... Nineβ‐cyclodextrin derivatives containing an amino group were synthesized via nucleophilic sub‐stitution from mono(6‐O‐p‐tolylsulfonyl)‐β‐cyclodextrin and used in asymmetric biomimetic Mi‐chael addition reactions in water at room temperature. The mechanism responsible for the moder‐ate activity and enantioselectivity of the β‐cyclodextrin derivatives was explored using nuclear magnetic resonance spectroscopy, namely 2D 1H rotating‐frame overhauser effect spectroscopy (ROESY), ultraviolet absorption spectroscopy, and quantum chemical calculations, which provide a useful technique for investigating the formation of inclusion complexes. The effects of the pH of the reaction medium, theβ‐cyclodextrin derivative dosage, the structure of the modifying amino group, and various substrates on the yield and enantioselectivity were investigated. The results indicated that these factors had an important effect on the enantiomeric excess (ee) in the reaction system. Experiments using a competitor for inclusion complex formation showed that a hydrophobic cavity is necessary for enantioselective Michael addition. A comparison of the reactions using 4‐nitro‐β‐nitrostyrene and 2‐nitro‐β‐nitrostyrene showed that steric hindrance improved the enan‐tioselectivity. This was verified by the optimized geometries obtained from quantum chemical cal‐culations. An ee of 71%was obtained in the asymmetric Michael addition of cyclohexanone and 2‐nitro‐β‐nitrostyrene, using (S)‐2‐aminomethylpyrrolidine‐modified β‐CD as the catalyst, in an aqueous buffer solution, i.e., CH3COONa‐HCl (pH 7.5). 展开更多
关键词 Β-CYCLODEXTRIN MODIFICATION Enantioselective Michael addition Quantum chemistry calculation
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Preparation and Physicochemical Characterization of Quercetin-HP-β-CD Inclusion Complexes 被引量:3
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作者 杨照罡 古丽斯坦.阿吾提 +6 位作者 曹轶 朱静 伍博深 王坚成 吕万良 张烜 张强 《Journal of Chinese Pharmaceutical Sciences》 CAS 2006年第2期69-75,共7页
Aim To prepare and characterize the QURC-HP-β-CD inclusion complexes and investigate the thermodynamic parameters of the process. Methods QURC-HP-β-CD inclusion complexes were prepared by the grinding method. The eq... Aim To prepare and characterize the QURC-HP-β-CD inclusion complexes and investigate the thermodynamic parameters of the process. Methods QURC-HP-β-CD inclusion complexes were prepared by the grinding method. The equilibrium inclusion constants and thermodynamic parameters were determinated by phase solubility analysis. Dissolution tests were performed to study the dissolution rate of inclusion complexes. The formation of inclusion complexes was confirmed by differential scanning calorimetry ( DSC), infrared spectroscopy (IR) , powder X-ray diffractometry (PXRD) and scanning electron microscopy (SEM). Results The aqueous solubility of quercetin was greatly increased ( about 37 folds) by inclusion technique, and the initial dissolution rate was markedly improved (10 folds) in the first 5 min. The results of DSC and SEM photographs showed that quercetin crystal disappeared in inclusion complexes, which indicated the formation of new phase. FT-IR spectra showed that the carbonyl quercetin crystal grinding method. absorption band of quercetin was shifted. PXRD showed that the diffraction peak of disappeared. Conclusion QURC-HP-β-CD inclusion complexes are produced by the The solubility of quercetin is improved by the inclusion technique. 展开更多
关键词 QUERCETIN HYDROXYPROPYL-Β-CYCLODEXTRIN inclusion complex inclusion constant Phase behavior
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Modified carbothermal reduction method for synthesis of LiFePO_4/C composite 被引量:1
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作者 尹艳红 李少玉 +2 位作者 闫琳琳 张会双 杨书廷 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第3期621-626,共6页
With LiAc-2H2O as Li precursor,pure olivine phase LiFePO4/C was synthesized at a relatively low temperature(650 ℃) and short sintering period(4 h) by molten salt carbothermal reduction method.Scanning electron mi... With LiAc-2H2O as Li precursor,pure olivine phase LiFePO4/C was synthesized at a relatively low temperature(650 ℃) and short sintering period(4 h) by molten salt carbothermal reduction method.Scanning electron micrograph shows that particle size of the product is about 1μm,smaller than that of the sample synthesized with Li2CO3 as Li precursor.Electrochemical measurements prove that LiFePO4/C obtained from LiAc-2H2O shows high capacity.The initial discharge capacities are 148 mA-h/g at 0.5C rate and 115 mA-h/g at 5C rate,respectively.After 50 cycles,the capacity retention ratios are 93% and 89% at 0.5C rate and 5C rate,respectively. 展开更多
关键词 LiFePO4/C composite molten salt carbothermal reduction Β-CYCLODEXTRIN
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Molecular Cloning and Expression of Carotenogenic Genes in Yellowish and Mutant Whitish Loquat (Eriobotrya japonica) Fruits 被引量:2
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作者 孙淑霞 谢红江 +3 位作者 陈栋 李靖 涂美艳 江国良 《Agricultural Science & Technology》 CAS 2013年第7期941-945,共5页
ObjectiveThe study aimed to explore the factors regulating carotenoid accumulation in flesh color. MethodA loquat mutation (red-or orange-fleshed plant emerged a bud mutation of white-flesh in trunk) was used as mat... ObjectiveThe study aimed to explore the factors regulating carotenoid accumulation in flesh color. MethodA loquat mutation (red-or orange-fleshed plant emerged a bud mutation of white-flesh in trunk) was used as material; HPLC analysis of β-carotene content was conducted. ResultThe β-carotene concentration in the flesh of wild and mutant types was 60.9 and 4.6 μg/g fresh weight, respectively. According to the conserved regions of genes from rose family genome, carotenogenic gene fragments in wild and mutant types were obtained. No nucleotide variation of the carotenogenic gene fragments was observed between wild and mutant genome. Real-time quantitative polymerase chain reaction (Q-PCR) was compared and one carotenogenic gene, β-ring hydroxylase (HYB) were considerably suppressed in mature mutant loquat fruits compared with that in wild. The other six carotenogenic genes were also expressed but the expression patterns appeared to be not correlated with the amount of β-carotene concentration in wild loquat flesh. ConclusionThe mutant whitish loquat lacks the ability to synthesize β-carotene because of the transcriptional down-regulation of carotenogenic gene HYB. 展开更多
关键词 Β-CAROTENE β-ring hydroxylase Flesh colour Gene expression LOQUAT
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Efficient oxidation of cinnamon oil to natural benzaldehyde over β-cyclodextrin-functionalized MWCNTs 被引量:5
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作者 杨祖金 张侠 +2 位作者 方岩雄 芮泽宝 纪红兵 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2016年第12期2086-2097,共12页
We have designed and prepared β-cyclodextrin (β-CD)-functionalized multi-walled nanotubes (MWCNTs-g-CD) for the oxidation of cinnamon oil to natural benzaldehyde under aqueous condi- tions. The synergistic effec... We have designed and prepared β-cyclodextrin (β-CD)-functionalized multi-walled nanotubes (MWCNTs-g-CD) for the oxidation of cinnamon oil to natural benzaldehyde under aqueous condi- tions. The synergistic effect of combining MWCNTs with β-CD led to a remarkable increase in the performance of the MWCNTs-g-CD for the catalytic oxidation of cinnamaldehyde, which exhibited 95% cinnamaldehyde conversion and 85% selectivity to natural benzaldehyde with a short reaction time of 10 rain. The MWCNTs-g-CD also exhibited outstanding recyclability with good stability, showing no discernible decrease in their catalytic activity over five reaction cycles. 展开更多
关键词 β-cyclodextrinCinnamon oilSelective oxidation Benzaldehyde Multi-walled carbon nanotube Synergistic effect
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Combined effect of hydroxypropyl-β-cyclodextrin and media pH on the solubility of prostaglandin E_1 被引量:1
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作者 谷福根 吴春芝 高永良 《Journal of Chinese Pharmaceutical Sciences》 CAS 2007年第2期112-115,共4页
Aim To investigate the combined effect of hydroxypropyl-β-cyclodextrin (HP-β-CD) and media pH on the solubility of prostaglandin E1 (PGE1) and construct a theoretical equation for the drug solubility as a functi... Aim To investigate the combined effect of hydroxypropyl-β-cyclodextrin (HP-β-CD) and media pH on the solubility of prostaglandin E1 (PGE1) and construct a theoretical equation for the drug solubility as a function of HP-β-CD concentration and media pH. Methods The solubility of PGE1 under different pH conditions was determined. Then, the drug solubility in different concentrations of HP-β-CD acidic or pH neutral solutions was measured, respectively. Finally, a theoretical solubility equation for the drug as a function of HP-β-CD concentration and media pH was deduced and confirmed in experiment. Results PGEs was solubilized by HP-β-CD or by increasing media pH. The drug solubility as a function of HP-β-CD concentration was found to follow the AL-type complexation model in acidic or neutral pH media, suggesting that both the ionized and neutral drugs form 1:1 molecular ratio complexes. Conclusions The solubility of PGE1 may be improved by increasing media pH or by using HP-β-CD as a solubilizer. HP-β-CD and media pH can produce combined effect on the solubility of PGE1. The deduced equation for the drug solubility in this study effectively characterizes the roles of HP-β-CD and media pH in determining total solubility of the drug. 展开更多
关键词 PGE1 HP-β-CD PH SOLUBILITY COMPLEXATION Theoretical equation
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Separation Properties of a New Polysiloxane-Anchored β-Cyclodextrin Derivative as Gas Chromatography Stationary Phase 被引量:1
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作者 史雪岩 傅若农 顾峻岭 《Journal of Beijing Institute of Technology》 EI CAS 2002年第3期285-289,共5页
A new capillary gas chromatography stationary phase, monokis (2,6 di O benzyl 3 O propyl (3’)) hexakis(2,6 di O benzyl 3 O methyl) β CD bonded polysiloxane, was synthesized. It ex... A new capillary gas chromatography stationary phase, monokis (2,6 di O benzyl 3 O propyl (3’)) hexakis(2,6 di O benzyl 3 O methyl) β CD bonded polysiloxane, was synthesized. It exhibited separation abilities to disubstituted benzene isomers and some chiral solutes. It was also found that the polarity of CD derivatives can be lowered both by chemically bonding it to polysiloxane and by diluting it in polysiloxane. The separation abilities of the polysiloxane anchored CDs (SP CD) are higher than that of the unbonded CDs (S CD) and the diluted S CD at lower column temperature. Hydrosilylation reaction is one of the best methods to lower the operating temperature of CDs. 展开更多
关键词 capillary gas chromatography stationary phase polysiloxane anchored β cyclodextrin derivative di substituted benzene isomers separation enantiomers separation
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Homological properties of modules characterized by matrices
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作者 张小向 陈建龙 《Journal of Southeast University(English Edition)》 EI CAS 2005年第2期239-243,共5页
Some homological properties of R-modules were investigated by matrices over aring R. Given two cardinal numbers α, β and an α x β row-finite matrix A, it was proved thatExt_R^1(R^((α))/R^((β))A, M) = 0 if and on... Some homological properties of R-modules were investigated by matrices over aring R. Given two cardinal numbers α, β and an α x β row-finite matrix A, it was proved thatExt_R^1(R^((α))/R^((β))A, M) = 0 if and only if M_α/r_(M_α)(R^((β))A) ≈ Hom_R(R^((β))A,M) ifand only if r_(M_β)l_(R^((β)))(A) = AM_α. Thus, the notion of (m,n)-injectivity was extended.Moreover, ( α, β) -flatness was characterized via annihilators of matrices, factorizations ofhomomorphisms as well as homological groups so that (m, n)-flat modules, f-projective modules andn-projective modules were consolidated under the notion of (α, β)-flat modules. Furthermore, acharacterization of left R-ML modules and some equivalent conditions for R^((β)) to be left R-MLwere presented. Consequently, the notions of coherent rings, (m, n)-coherent rings and π-coherentrings were consolidated under that of (α, β)-coherent rings. 展开更多
关键词 β)-injective module β) -flat module R-ML module β)-coherent ring
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Effect of Fish Oil on (-Adrenoceptors and the Activity of Adenylate Cyclase on Myocardial Membrane in Rats
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作者 周建政 吴葆杰 张岫美 《Journal of Chinese Pharmaceutical Sciences》 CAS 1996年第3期154-159,共6页
Effects of fish oil on β-adrenoceptors as well as the activity of adenylate cyclase (AC) on rat myocardial membrane were investigated.Supplementation with fish oil had no significant effect on basal activity of AC on... Effects of fish oil on β-adrenoceptors as well as the activity of adenylate cyclase (AC) on rat myocardial membrane were investigated.Supplementation with fish oil had no significant effect on basal activity of AC on myocardial membrane whereas it could markedly inhibit the AC activity stimulated by isoproterenol (ISO). Radioligand binding assays showed that supplementation with fish oil had no effect on Bmax and Kd, compared with saline control. However, supplementation with sheep oil could markedly reduce both the Kd and Bmax, compared with saline control. And the Kd of sheep oil group was greatly decreased than that of fish oil group. The results suggested that supplementation with fish oil mainly affected the activation of AC, not β-adrenoceptor itself. 展开更多
关键词 Fish oil EPA and DHA Adenylate cyclase Β-ADRENOCEPTOR
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Spectral Differences of the Molecule-ion Adducts of β-Cyclodextrin and Lithium Carbonate 被引量:2
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作者 柏雷 宋乐新 +1 位作者 王莽 朱林红 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2010年第1期117-124,I0002,共9页
A small shielding effect on the hydrogen atoms of chiral carbons of β-cyclodextrin (β-CD) was detected by 1H nuclear magnetic resonance, but a large environmental change of the chiral carbon atoms at high concentr... A small shielding effect on the hydrogen atoms of chiral carbons of β-cyclodextrin (β-CD) was detected by 1H nuclear magnetic resonance, but a large environmental change of the chiral carbon atoms at high concentration ratios of lithium carbonate (Li2CO3) to β-CD was observed by polarimetry in aqueous solution. These findings urged us to investigate whether different formation conditions of the molecule-ion system between Li2CO3 and β-CD in solid state were involved in different spectral performances. To answer the question, we prepared three adducts of Li2CO3 to β-CD, i.e., samples 1, 2, and 3, by magnetic stirring, solvothermal and grinding conditions, respectively. Powder X-ray diffraction and Fourier transformation infrared spectroscopy provided the information of formation of the three molecule-ion adducts. Besides, scanning electron microscope images provided different surface information of the three adducts. Further, significant spectral differences in thermal behavior of these adducts were found by thermogravimetry and derivative thermogravimetry. 展开更多
关键词 Β-CYCLODEXTRIN Li2CO3 Molecule-ion interaction ADDUCT
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Covalent Assembly of Penicillin Acylase in Mesoporous Silica Based on Macromolecular Crowding Theory 被引量:11
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作者 王安明 周成 +3 位作者 王华 沈树宝 薛建跃 欧阳平凯 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2007年第6期788-790,共3页
To improve the covalent immobilization of penicillin acylase (PA), macromolecular crowding theory was applied to its immobilization. Influence of mass ratio of enzyme to the silica, as well as, activation time with ... To improve the covalent immobilization of penicillin acylase (PA), macromolecular crowding theory was applied to its immobilization. Influence of mass ratio of enzyme to the silica, as well as, activation time with glutaraldehyde on the activity of assembled PA, was studied. In the mesopores, the effect of fl-cyclodextrin (β-CD) on the immobilization of the enzyme was also investigated. It was remarkable that the coupled yield and relative activity reached 99.5% and 92.3%, respectively, when penicillin acylase assembled covalently in the mesopores. The results here indicate that mimicked macromolecule crowding could significantly ameliorate the performance of covalently immobilized PA. 展开更多
关键词 enzyme immobilization penicillin acylase Β-CYCLODEXTRIN macromolecule crowding
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An efficient and stable Cu/SiO_2 catalyst for the syntheses of ethylene glycol and methanol via chemoselective hydrogenation of ethylene carbonate 被引量:7
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作者 Jiaju Liu Peng He +3 位作者 Liguo Wang Hui Liu Yan Cao Huiquan Li 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2018年第8期1283-1293,共11页
The efficient synthesis of methanol and ethylene glycol via the chemoselective hydrogenation of ethylene carbonate(EC) is important for the sustainable utilization of CO_2 to produce commodity chemicals and fuels. I... The efficient synthesis of methanol and ethylene glycol via the chemoselective hydrogenation of ethylene carbonate(EC) is important for the sustainable utilization of CO_2 to produce commodity chemicals and fuels. In this work, a series of β-cyclodextrin-modified Cu/SiO_2 catalysts were prepared by ammonia evaporation method for the selective hydrogenation of EC to co-produce methanol and ethylene glycol. The structure and physicochemical properties of the catalysts were characterized in detail by N_2 physisorption, XRD, N_2O titration, H_2-TPR, TEM, and XPS/XAES. Compared with the unmodified 25 Cu/SiO_2 catalyst, the involvement of β-cyclodextrin in 5β-25 Cu/SiO_2 could remarkably increase the catalytic activity—excellent activity of 1178 mgEC g_(cat)^(–1) h^(–1) with 98.8%ethylene glycol selectivity, and 71.6% methanol selectivity could be achieved at 453 K. The remarkably improved recyclability was primarily attributed to the remaining proportion of Cu~+/(Cu^0+Cu~+). Furthermore, the DFT calculation results demonstrated that metallic Cu^0 dissociated adsorbed H_2, while Cu~+ activated the carbonyl group of EC and stabilized the intermediates. This study is a facile and efficient method to prepare highly dispersed Cu catalysts—this is also an effective and stable heterogeneous catalyst system for the sustainable synthesis of ethylene glycol and methanol via indirect chemical utilization of CO_2. 展开更多
关键词 Ethylene carbonate Hydrogenation Β-CYCLODEXTRIN Cu/SiO2 Methanol Ethylene glycol
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